🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Author: gcf-owl-bot[bot]

noxfile.py

@@ -294,8 +294,18 @@ def install_systemtest_dependencies(session, *constraints):
 
 
 @nox.session(python=SYSTEM_TEST_PYTHON_VERSIONS)
-@nox.parametrize("database_dialect", ["GOOGLE_STANDARD_SQL", "POSTGRESQL"])
-def system(session, database_dialect):
+@nox.parametrize(
+ "protobuf_implementation,database_dialect",
+ [
+ ("python", "GOOGLE_STANDARD_SQL"),
+ ("python", "POSTGRESQL"),
+ ("upb", "GOOGLE_STANDARD_SQL"),
+ ("upb", "POSTGRESQL"),
+ ("cpp", "GOOGLE_STANDARD_SQL"),
+ ("cpp", "POSTGRESQL"),
+ ],
+)
+def system(session, protobuf_implementation, database_dialect):
  """Run the system test suite."""
  constraints_path = str(
  CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
@@ -329,6 +339,12 @@ def system(session, database_dialect):
 
  install_systemtest_dependencies(session, "-c", constraints_path)
 
+ # TODO(https://github.com/googleapis/synthtool/issues/1976):
+ # Remove the 'cpp' implementation once support for Protobuf 3.x is dropped.
+ # The 'cpp' implementation requires Protobuf<4.
+ if protobuf_implementation == "cpp":
+ session.install("protobuf<4")
+
  # Run py.test against the system tests.
  if system_test_exists:
  session.run(
@@ -338,6 +354,7 @@ def system(session, database_dialect):
  system_test_path,
  *session.posargs,
  env={
+ "PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION": protobuf_implementation,
  "SPANNER_DATABASE_DIALECT": database_dialect,
  "SKIP_BACKUP_TESTS": "true",
  },
@@ -350,6 +367,7 @@ def system(session, database_dialect):
  system_test_folder_path,
  *session.posargs,
  env={
+ "PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION": protobuf_implementation,
  "SPANNER_DATABASE_DIALECT": database_dialect,
  "SKIP_BACKUP_TESTS": "true",
  },